Method and apparatus for trimming and finishing plastic jars

ABSTRACT

Method and apparatus for trimming and finishing in one operation plastic jars produced with a flange extending from the mouth thereof. A revolving cutter blade engages the edge of the mouth of the jar, and as the blade advances it cuts the flange from the jar. When the blade has cut the jar to the desired length, a gauge stops the blade&#39;&#39;s advance allowing it to finish the sealing surface of the jar. The stringy scrap is guided into stationary chip breakers which reduce the scrap into smaller pieces.

United States Patent 1191 Humphreys et al.

METHOD AND APPARATUS FOR TRIMMING AND FINISHING PLASTIC JARS Inventors:Robert Lee Humphreys, Saint Charles; James Edward Spitzer, North Aurora,both of 111.

American Can Company, Greenwich, Conn.

Filed: Aug. 30, 1971 Appl. No.: 176,151

Assignee:

US. Cl 408/1, 408/36, 408/87, 29/33 S, 83/914, 425/292, 425/307 Int. ClB23b 35/00 Field of Search 408/1, 22, 28, 36, 408/44, 52, 117, 118, 224,241 R, 87;

References Cited UNITED STATES PATENTS 7/1968 Brown 83/914 X Oct. 16,1973 3,417,428 12/1968 Rupert 83/914 3,564,655 2/1971 Smith 425/307 x3,610,768 10/1971 Cochran 408/204 3,540,324 11/1970 Johansson 408/227Primary Examiner-Gil Weidenfeld Att0rneyR0bert P. Auber et al.

Method and apparatus for trimming and finishing in one operation plasticjars produced with a flange extending from the mouth thereof. Arevolving cutter blade engages the edge of the mouth of the jar, and asthe blade advances it cuts the flange from the jar. When the blade hascut the jar to the desired length, a gauge stops the blades advanceallowing it to finish the sealing surface of the jar. The stringy scrapis guided into stationary chip breakers which reduce the scrap intosmaller pieces.

ABSTRACT 3 Claims, 11 Drawing Figures H ."ll-llllll VIII;

PMENIEDncI 16 1975 SHEET 3 BF 3 2i llul 1477'0RNE) METHOD AND APPARATUSFOR TRIMMING AND FINISHING PLASTIC JARS BACKGROUND OF THE INVENTION Thepresent invention relates to trimming and finishing in one operationplastic jars produced with a flange extending from the mouth of the jar,and more particularly t thermoplastic jars formed on a web.

In the production of jars having a flange extending from the mouththereof, such as jars which are thermoformed on a web, there is no knownmethod or apparatus for trimming away the flange from the jar andfinishing the sealing surface of the jar in one operation. The presentinvention provides such a one-step trimming and finishing method, aswell as apparatus to execute the method, and is particularly unique inthat the sealing surface, also being the finished surface, lacks any dieparting lines.

SUMMARY OF THE INVENTION The instant invention comprises a method fortrimming and finishing an annular, plastic jar produced with a flangeextending from the mouth of the jar. The method includes axiallyadvancing a revolving cutter blade to engage the edge of the mouth ofthe unfinished jar, trimming the flange from the jar with the revolvingcutter blade, and stopping the cutter blades axial advance, therebyfinishing the jars sealing surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of thetrimming apparatus of the present invention and the plastic jar prior tothe trimming and finishing operation.

FIG. 2 is an elevational view of the apparatus of FIG. 1 in the trimmingand finishing position.

FIG. 3 is a central vertical sectional view of the apparatus of FIG. 2.

FIG. 4 is central vertical section of the apparatus and jar after thetrimming and finishing operation, the lower portion in elevation,showing the finished sealing surface of the jar.

FIG. 5 is a horizontal sectional view taken on the plane indicated bythe line 5-5 of FIG. 4.

FIG. 6 is an enlarged, fragmentary perspective view of the cutter bladeassembly used in the trimming apparatus.

FIG. 7 is an enlarged, fragmentary plan view of the revolving cutterblade and an enlarged, fragmentary sectional view of the jar sidewallprior to the trimming and finishing operation.

FIG. 8 is an enlarged, fragmentary elevational view taken on the planeindicated by the line 8-8 of FIG. 7.

FIG. 9 is an enlarged, fragmentary, vertical sectional view of thecutter blade assembly and jar in the trimming and finishing position.

FIG. 10 is a vertical sectional view taken on the plane indicated by theline 10-10 of FIG. 9.

FIG. 11 is a horizontal sectional view taken on the plane indicated bythe line l1ll of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT We refer now to the drawings todescribe the preferred embodiment of the instant invention. The methodof the instant invention is best represented by FIGS. 1 and 2, wherein aplastic jar having a flange 22 extending from the mouth 23 thereof is tobe severed from a plastic web 24 and finished on its sealing surface 27.The jar 20 is generally formed by thermoforming techniques, but theinvention is not limited to the manner of forming the jar 20.

The web 24 is advanced intermittently upon a feeding table 26 having anaperture 25 by conventional means not shown until the jar 20 is properlyaligned with a holding pocket 28 and a trimmer assembly 32 for thetrimming and finishing operation. The holding pocket 28 is then loweredby conventional drive means 30 from the open position indicated in FIG.I to the closed position indicated in FIG. 2. Finally, the trimmerassembly 32, which includes a revolving cutter blade 34 having a shank37 (as shown in FIG. 5), a series of chip breakers 36, a spring loadedpilot 38 and a trimming pilot 40, is raised by conventional drive means42 from the open position indicated in FIG. 1 to the closed positionindicated in FIG. 2.

The chip breakers 36 are fixed to a stationary cylinder 47, whichcylinder 47 is fixed to the drive means 42 by a set screw 49. The cutterblade 34 is fixed to a cylinder 35 by means of two set screws 39 whichsecure the cutter blade shank 37 to the cylinder 35, which in turn isrotated by a first shaft 43 which in turn is rotated by a second shaft45 through a pin 55 and conventional drive means not shown. A set screw41 fixes the cylinder 35 to the rotating shaft 43.

For a detailed discussion of the apparatus and its manner offunctioning, referenceis now made to FIGS. 3-11. As best seen in FIGS. 3and 4, the holding pocket 28 is provided with a rubber gasket 44 and anopening 46 for maintaining a vacuum while transporting the trimmed andfinished jar 20 to a packing table not shown. The rubber gasket 44 alsoprovides friction with the jar 20 to prevent rotation during trimmingand finishing, and accommodates irregularities of height when multipleposition trimming machines are used.

FIG. 3 also illustrates the spring loaded pilot 38 engaging the trimmingpilot 40, thereby guaging the trimming and finishing depth. The springloaded pilot 38 includes a coil spring 53 held in place by a washer 64and a recess 66 in the spring loaded pilot 38. As the trimmer assembly32 is advanced axially upwardly, to engage the inside surface of theconcave bottom wall 68 of the jar 20, the holding pocket 28 is loweredapproximately simultaneously (for high speed manufacture) to engage theoutside surface of the concave bottom wall 68. Once the spring loadedpilot 38 engages the concave wall 68, the trimmer pilot 40 continues toadvance and remove plastic on the mouth 23 of the jar 20 until therecessed wall 70 of the trimming pilot 40 engages the annular surface 72of the spring loaded pilot 38, thereby determining the amount of plasticto be trimmed and the height of the jar 20.

FIG. 4 illustrates the jar 20 held within the holding pocket 28 by meansof a vacuum applied through opening 46. The jar 20 may now betransferred for subsequent discharge from the pocket 28. The springloaded pilot 38 is now in its extended position, preparatory for thenext trimming cycle. Also seen in FIG. 4 is the portion of the web 24remaining after the trimming operation.

As the revolving cutter blade 34 is axially advanced to the closedposition, it trims the jar 20 from the flange 22 by removing the plasticon the mouth 23 of the jar 20 adjacent the flange 22, indicated in FIG.10 by the area 48 within the dotted lines. The design of the cutterblade 34, to be discussed hereinafter, is responsible for guiding thestringy scrap 40 (FIGS. 3 and 9) into the stationary chip breakers 36.Once the trimming depth is reached, further rotation of the cutter blade34 results in finishing the sealing surface 27 of the jar 20 (FIG. 4).Because the sealing surface 27 is the surface that is trimmed andfinished, it lacks any die parting lines or other defects arising fromthe method of forming the jar 20.

The chip breakers 36 and the unique design of the cutter blade 34 arethe main elements which permit the method and apparatus presentedherewith to function on a continuous basis, or even at all. For withoutmeans to guide the stringy scrap 50 away from the jar 20 and the cutterblade 34, the apparatus would soon become entangled with the stringyscrap 50 produced thereby.

Reference is now made to FIGS. 6-11 in describing the cutter blade 34and chip breakers 36. FIG. 6 illustrates the design of the cutter blade34 which not only trims and finishes the jar 20, but also guides thescrap 50 into the chip breakers 36. The cutter blade 34 includes acutting edge 54 which trims and finishes the jar 20 by removing plasticon the jar 20 adjacent the flange 22, and a scrap guide 56 spaced fromand situated forward of the cutting edge 54 which guides the stringyscrap 50 into the chip breakers 36. The edge 58 of the base of thecutter blade 34 shears the scrap 0 asit approaches the chip breaker 36,thereby breaking the scrap 50 into several smaller pieces which can thenbe conveyed away from the trimming apparatus by air or other means notshown (FIG. 9). The scrap 50 is forced into the chip breakers 36 owingto the scrap guide 56, which is shown to provide an enclosed passageway60 forward of the cutter blade 54. The guide '56 need not .4 7 providesuch an enclosed 'passagew'ayebut need only be of such design as toinsure the scrap 50 being guided into the chip breakers 36.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description and it will beapparent that various changes may be made in the form, construction andarrangement of the parts of the article and that changes may be made inthe steps of the method described and their order of accomplishmentwithout departing from the spirit and scope of the invention orsacrificing all of its material advantages, the form hereinbeforedescribed being merely a preferred embodiment thereof.

What is claimed is:

l. A method for trimming and finishing the sealing surface of anannular, plastic jar produced with a flange extending from the mouththereof, comprising the steps of:

axially advancing a revolving cutter blade to engage the edge of themouth of said jar;

trimming the flange from the jar with the revolving cutter blade;

guiding the stringy scrap produced by the cutter blade into stationarychip breakers, thereby reducing said scrap into smaller pieces; and

stopping the cutter blade s axial advance, thereby finishing the jarssealing surface.

2. The method of claim 1 comprising the additional step of surroundinglysupporting the jar during the trimming and finishing steps.

3. The method of claim 2 wherein the plastic is thermoplastic and thejar is produced on a web by thermoforming.

1. A method for trimming and finishing the sealing surface of anannular, plastic jar produced with a flange extending from the mouththereof, comprising the steps of: axially advancing a revolving cutterblade to engage the edge of the mouth of said jar; trimming the flangefrom the jar with the revolving cutter blade; guiding the stringy scrapproduced by the cutter blade into stationary chip breakers, therebyreducing said scrap into smaller pieces; and stopping the cutterblade''s axial advance, thereby finishing the jar''s sealing surface. 2.The method of claim 1 comprising the additional step of surroundinglysupporting the jar during the trimming and finishing steps.
 3. Themethod of claim 2 wherein the plastic is thermoplastic and the jar isproduced on a web by thermoforming.